Metal-coating process.



I No Drawing.

barren snares Ara orrica.

JAY G. BENEKER, OF CINCINNATI, OHIO.

METAL-COATING PROCESS.

To all whom it may concern:

Be it known that I, JAY C. BENEKER, a citizen of the United States,residing at- Cincinnati, in the county of Hamilton and State of Ohio,have invented certain new and useful Improvements in Metal-CoatingIrocesses, of which the following is a specification containing such afull, clear, and exact description as will enableany one skilled in theart to use the same.

My invention deals with the art of'coating relatively corrosive metalswith a protecting film; and it is concerned more especially with amethod whereby a uniform and continuous film of lead or alloys thereofmay be successfully and tenaciously applied to surfaces of iron.-

Heretofore sheet iron has been coated with tin forming what istechnically known as terne plate, or more commonly'as tin plate; butowing to thehigh price of metallic tin, this material, while having manyadvantages, is quitecostly. In an effort to economize, the iron has beencoated with zinc; forming what is currently lmown as galvanized iron,but not without the sacrifice of the superior physical and lastingqualities of the terne plate. The unsatisfactory features of galvanizediron have been well recognized, and therefore to find a commerciallysatisfactory way of producing a better substitute, and one less costlythan tin plate, has been the goal for which those most skilled in theart have long striven.

I Now, this invention is based 'oncertain metallurgical and physicaldiscoveries and an application thereof such that iron surfaces may beperfectly coated with a film of lead-or a lead-alloy so as mosteffectively to protect. the iron against corrosion, and at a relativelylow cost and by a process en-' tirely feasible from the standpoint ofall commercial requirements.

' Lead, as it is known to the commercial world, varies in cost dependingupon its purity, 71. e., upon the amount of antimony with which it isalloyed. That is to say, .what is commonly known as hard lead contains aconsiderable amount of antimony,

while soft lead may be quite free of this common alloying metal. In .allits grades, this" metalleadis less costly than tin, while on the otherhand it is vastly superior to zinc as a resistant to corrosion. By meansof this invention, it is now made possible Specification of LettersPatent.

Patented June 29, 1915..

Application filed August 18, 1911. Serial No. 644,888.

perfectly to coat iron with such lead or its said alloys.

It has for long been recognized that lead is to a high degree proofagainst corrosion and this metal. has been rolled into sheets isnecessary because otherwise they would not be of sufiicient strength topermit of handllng or servicelead being of little strength. Therefore,many efforts have hitherto been bent without success to produce on asheet iron backing a tissue-like film of lead s0 uniformly andcontinuously as to avoid pin-holes or openings exposing the corrodibleiron, and adhering with, such tenacity as to prevent blistering orseparation, either byhandling or subsequent use.

By resorting to the method herein disclosed, those skilled in this artwill be enabled perfectly to coat surfaces of iron with lead or itsalloys, and to do so rapidly, eflectively and economically, and fromevery standpoint in a strictly practical and commercial way. In carryingout this process, the iron surface will first be cleared from scale andoxids in any suitable conventional manner, and is thereupon subjected toa suitable flux, preferably of zinc chlorid and submerged in a meltedbath of lead containing a small proportion of cadmium. .I havediscovered that lead in its various commercial grades, while ordinarilypossessing little affinity for iron, will in the presence of metalliccadmium, even in very small quantities, amalgamate with the iron surfaceso as perfectlyto coat the same with a very thin film. Under ordinarypractical working conditions where commercial considerations areparamount, I preferably use amounts of cadmium ranging from even sosmall an amount as .170 under excellent running conditions up topercentages as high as moderate expense will warrant, say 1% or over.Cadmium is in itself a very expensive metal, and therefore, from acommercial standpoint I prefer to use the smaller proportions thereof inthe .bath. Inasmuch as cadmium, however, tends to oxidize and pass intothe I flux (/which would .necessitate additions of cadmium to the bathto maintain the ininior preventive ofthis action the step of adding tothe lead bath as much zinc as it will dissolve, say about Zinc beingmore readily oxidized than cadmium, it tends to pass into the flux inpreference to the cadmium, and by adding the same, the more expensivemetal may be conserved, especially when the bath contains considerablecadmium. A bath of this character has a. lower melting point than thatof pure lead, which is a feature of great advantage, in that it enablespalm oil fluxes to be used on the exit ends of the bath. This would beimpossible in the case of zinc for example, as the palm oil wouldvaporize and burn at the high melting point of zinc.

Iron coated in accordance with this process possesses many advantages.The small proportion of cadmium in the film of lead, being a metal morepositive than iron, tends to protect the iron in the same manner aszinc, and it exercises its positive features just as though it wasunalloyed by reason of the fact that it exists as an element in aeutectic solution in the lead. This cadmium also has the importantoffice of not only initially promoting the adherence of the lead film tothe iron surface, but also of subsequently maintaining that condition.This coating is superior to zinc by reason of its very malleablecharacter, so that in handling it does not tend to crack and opento-expo- 'sure portions of the underlying iron.

modifying, amplifying and inother ways i putting this invention intopractice. I

- therefore intend that the terms used in the foregoing disclosure andin the accompanying claims are to be taken in a general, not in aspecial, sense. Thus, by the term lead ,,I contemplate the variousgrades of lead now commercially known, ranging from soft lead, of greatpurity, to hard lead, containing considerable amounts of antimony, forexample.

I therefore claim as new and desire to secure by Letters Patent of theUnited States 1. A process of the nature disclosed for lead-coating ironsurfaces, consisting in initially obtaining a clean iron surface, andthen contacting the same with a fused leadbearing bath in the presenceof metallic cadmium.

2. A process of the nature disclosed for I lead-coating iron surfaces,consisting in contacting the iron surfaces at an elevated temperature,with an alloy containing lead and a relatively small proportion ofcadmium.

3. A process of the nature disclosed for lead-coating iron surfaces,consisting in oblead-coating iron surfaces, which consists in obtaininga melted bath of a commercial grade of lead and a small quantity of zincand cadmium, and then subjecting the cleaned iron surfaces to said bath.

JAY 0. BEN EKER. Witnesses:

F. C. LAWsoN, G. H. BEAZELL,

